* Make Waku.send a shim of MessagingClient.send
* At ReliableChannelManager mount time, set its default sendHandler
* Remove Waku ref from ReliableChannelManager
* Refactor channels to fit layering with explicit mount
* Fix channels test to perform the new mount sequence
* Add Waku.reliableChannelManager
* liblogosdelivery_start_node mounts ReliableChannelManager after MessagingClient
* Fix test_wakunode_peer_exchange missing lockNewGlobalBrokerContext
* Fix test_protocol missing lockNewGlobalBrokerContext
* Harden provider setup vs. misconfiguration (improper shared broker context situations)
